Health officials in Nigeria are celebrating an impressive milestone: The country has gone one year without a single case of polio. The world is now one step closer to making polio the second human infectious disease – after smallpox – to be eradicated with an effective vaccination campaign.

Nigeria is now on the brink of eradicating the paralyzing disease, which predominately affects children under five. Polio (poliomyelitis) is a highly infectious disease, which invades the nervous system and can at times paralyze a victim in a matter of hours. The disease is caused by a virus that spreads through unhygienic environments. One in 200 infections leads to irreversible paralysis and 5% to 10% among those paralyzed die.